L87 6.2: “NHTSA to investigate potential for engine failure in nearly 1 million GM trucks, SUVs”

[Marky Dissod]

Pardon me for being redundant, but the last time I posted this was in another thread about failure-prone 6.2L V8s from last year.

Tyler Durden was explaining his former job as a 'recall coordinator' for a 'major automobile manufacturer to another passenger.
His job was to apply 'The Formula' - should we initiate a recall?:
"Take
the number of vehicles in the field - A
multiply by
the probable rate of failure - B
then multiply (A*B) by
the average out-of-court settlement - C

(A*B)*C = X

"If 'X' is less than the cost of a recall ... WE DON'T DO ONE."

Funny thing is, the schidty cylinder (valve) deactivation hardware isn't even the problem here!

 

[jfoj]

Funny thing is, the schidty cylinder (valve) deactivation hardware isn't even the problem here!

Well the AFM/DFM is likely a good part of these failures. Not sure what really changed as of 2021 other than moving from AFM to DFM. But understand the overall oiling system path of these engines SUX. What did the boys from the 60's learn in racing, oil the main bearings FIRST and the valvetrain LAST. The oiling path of these 6.2l engines send oil to the AFM manifold, camshaft and lifters first, then the main bearings are feed oil after the valvetrain. So the problem is the front main bearing and the #1 and #2 rod bearings are LAST in the oiling path. Add the 2 stage oil pump, 0W20 engine oil, Auto Stop/Start, high oil consumption and fuel contamination due to Direct Injection to an already compromised engine design, what do you expect. Add to this that the oil pressure sensor is located in the AFM manifold on the REAR of the engine, almost at the beginning of the oil flow path, how does the engine management system really know when the best time to switch the 2nd stage of the oil pump in?

The real issue is what, if anything is GM going to do to completely resolve the problem? I suspect GM will issue a recall at some point with the flash update to the engine management system that will enable the 2nd state oil pump at a much earlier time, if not full time unless for some reason the DFM system would have a hard time with operating at a higher oil pressure.

At some point GM needs to understand almost all of these problems are oil system related.

Remember "It's the economy stupid", well for the later model GM V8 engines "It's the oiling system stupid!"

While this info does not include the later models, I am sure they are using the same style components - https://static.nhtsa.gov/odi/tsbs/2020/MC-10174305-9999.pdf

Info on AFM - https://gm-techlink.com/wp-content/uploads/2018/09/GM_TechLink_16_Mid-August_2018.pdf

This may be why the 5.3l is not as failure prone. Apparently the 5.3 does not have a 2 stage oil pump like the 6.2l. From this link - https://gm-techlink.com/wp-content/...ly-Tips-and-New-Information-February-2023.pdf

"Engine Oil Lubrication Description

We have seen numerous cases where OCV diagnosis and control has been attempted on engines that do not have oil control solenoids. Engine Lubrication Description Engine lubrication is supplied by a variable displacement single-stage (L82, L84) or two-stage (L87)vane-type oil pump assembly. An oil control solenoid valve, controlled by the engine control module (ECM), mounted to the two-stage oil pump provides dual stage functionality. The oil pump is mounted on the front of the engine block and driven directly by the crankshaft sprocket. The pump rotor and vanes rotate and draw oil from the oil pan sump through a pick-up screen and pipe. The oil is pressurized as it passes through the pump and is sent through the engine block lower oil gallery"

 

[PPK_]

Well the AFM/DFM is likely a good part of these failures. Not sure what really changed as of 2021 other than moving from AFM to DFM. But understand the overall oiling system path of these engines SUX. What did the boys from the 60's learn in racing, oil the main bearings FIRST and the valvetrain LAST. The oiling path of these 6.2l engines send oil to the AFM manifold, camshaft and lifters first, then the main bearings are feed oil after the valvetrain. So the problem is the front main bearing and the #1 and #2 rod bearings are LAST in the oiling path. Add the 2 stage oil pump, 0W20 engine oil, Auto Stop/Start, high oil consumption and fuel contamination due to Direct Injection to an already compromised engine design, what do you expect. Add to this that the oil pressure sensor is located in the AFM manifold on the REAR of the engine, almost at the beginning of the oil flow path, how does the engine management system really know when the best time to switch the 2nd stage of the oil pump in?

The real issue is what, if anything is GM going to do to completely resolve the problem? I suspect GM will issue a recall at some point with the flash update to the engine management system that will enable the 2nd state oil pump at a much earlier time, if not full time unless for some reason the DFM system would have a hard time with operating at a higher oil pressure.

At some point GM needs to understand almost all of these problems are oil system related.

Remember "It's the economy stupid", well for the later model GM V8 engines "It's the oiling system stupid!"

I don't know.. i think at least move to a 5w30 oil.. instead of the current spec. On top of this.. i think craftsmanship of the build is weaker.. somehow there is a more debris in engine earlier on. it is more than my 2018 engine.. i have a 2024 5.3 which i did first oil change at 1100 miles. i wish i did the first cycle at 100 miles.. at lot of debris in the change. i think... the smart thing is to 5w30, do 4k changes and get a warranty.

Anyway... you can see the magnet shows lot of metal in the filter. is this debris from the rockers needles? is from the lifters? is from other areas where clearances are not right? Not happy with motor.. though it not noisy with 1200 miles on it. i am going to warranty it 72/72. you don't have a choice.

 

[jfoj]

I did my first oil change at 500 miles, I still have the filter, have not cut it open yet. Will check and see what it looks like compared to your filter. I also am sending oil samples for analysis at each oil change to track possible future problems if I can detect anything unusual. I am also running magnets on the filter and a magnetic oil drain plug. My 2005 Yukon 6.0l came from the factory with a magnetic drain plug.

Fully agree with the 5W30 engine oil and 4000k oil change interval as well, more for oil staying in the bearing journals when the engine is shut down so you have a reduction of dry start up, but there clearly will be other benefits to include less problems with fuel dilution. HIGHLY recommend that you fill the sump to top of dipstick, 8.0 qts for an oil change is NOT enough. I am running 9 qts in my engine (flame suit on!) This put the oil level on the dipstick just slightly over the top hash mark. Check when engine is just turned off and you will see there is still oil in the top of the engine.

Almost wondering if it be worth a hack to command 2nd stage of oil pump on permanently for the 6.2l. It appears the 5.3l just has a variable displacement single stage oil pump, maybe this is why there are less 5.3l failures?? Assume this may cause a CEL and unclear if there would be other issues with the DFM system at the higher oil pressure? This L87 is brand new to me, so I have no real history or a full understanding yet of the oiling system and AFM craziness.

 

[CMoore711]

I'm being told indefinite wait on an engine, maybe 6 months. The dealer is suggesting I talk to them about trading it in for something else. Also that GM will only cover 1 week for a loaner? That's the part that is BS if it is true.

11,800 miles - needs new engine.

Loaner vehicles are owned and managed at each dealership level by the dealer their use is at their discretion. The "GM is only covering a loaner for 1 week" is BS from the dealer. Thats your dealership not willing to keep you in a loaner for extended periods of time until your vehicle is fixed.

You need to contact a local rental car company, get the daily rates for a Tahoe or Suburban (whatever size your GM SUV is that's needing the new engine) and tell the dealer that's the daily rental car cost you expect them to cover if they can't provide you a loaner for the time it takes to get your vehicle back. If your dealership is unwilling, then you need to start escalating your case with GM.

Or like I stated in post#6: Check the dealerships’ used vehicle inventory on the lot and ask for one of those. They got money in their used inventory, they own them, and it’s not like you’re asking for something brand new. Make them have some skin in the game and they’ll be more motivated to get your vehicle repaired and back to you sooner.